Nucleic acids will be sequenced and nucleic acid sequences will be analyzed for constraints on nucleotide order that may be a consequence of Genotypic Selection. Genotypic Selection is a novel form of selection postulated to exist at the intracellular level and acting directly on the nucleic acids before their expression. The constraints imposed on actual nucleotide sequences will be examined for patterns of internal terminator sequences, true palindromic sequences, self-complementary sequences and contexts of nucleotide groups. Proposed secondary structures for sequences greater than 1000 nucleotides have been generated (0X174, (tRNA, 5S), MS2). It can be shown that tRNA secondary structure is not a consequence of maximum base pairing. The sequencing of fl bacteriophage is progressing. Methods employed are the Sanger -Coulson plus-minus system, and the Sanger dideoxy method. In addition, the nature of tRNA-mRNA interactions are being examined to determine the actual number of base pairs per interaction. A model proposed by Crick, Klug, Brenner and myself is being tested. The significance of such studies is that they allow a test of the predictions of Genotypic Selection; a perspective where the genotype is a phenotype for syntactical and structural selection by the replication, transcriptional and translational machinary.